Tall Pinebarren Milkwort
Today John and George walked Jonathan Dickinson State Park near Hobe Sound and decided unanimously that a wildflower may enter our blog for sheer floral performance. Today’s star was Tall Pinebarren Milkwort forming a galaxy of countless waist-high lemon yellow wands along the shallow marshy shores. The wands extending ever-smaller toward the horizon are an artist’s lesson in perspective. You could scarcely find a happier wildflower, except maybe its doppelganger, the Low Pinebarren Milkwort (P. ramosa) which differs by having broad (vs. nearly linear) leaves in its disappearing basal rosette. These species are biennials or probably sometimes annuals.
That floral showcase has to attract somebody. Who knows what list of insects stop by? Recorded in the literature is a leafcutter bee (Megachile brevis pseudobrevis). The bee, interestingly, can make its cylindric home cells of cut leaf pieces in grassy places, such as the marsh occupied by the TPBMW, in contrast with the woody haunts of most leafcutters. Of course the bee and the flower have broader social circles than each other.
Why are Milkworts called Milkworts? Wort is an old name for an herbaceous plant, but why the milk? Do they lactate when fractured? No. The botanical name Polygala translates loosely from Greek “mega moojuice,” and reflects an ancient belief in the ability of Polygala to keep the cows drippy.
The cow connection may tie in somehow with root aromas associated with many Polygala species, although apparently not our swampy P. cymosa. Polygala is a a huge worldwide genus, and some species have roots smelling of wintergreen, this probably explaining the name “candyroot” applied to some. That wintergreen fragrance comes from a derivative of salicylic acid, more or less aspirin, and this in turn partly explains the popularity of Polygala root in traditional medicines, especially in Asia, where among other benefits, you can use root extracts to quit smoking. (Don’t try it— they contain toxic saponins and who knows what other forms of bioactivity?) The point here is, if you want a genus where the roots have served to treat just about everything, here it is.
Another stellar quality of Polygala is its diversity in floral colors and arrangements. They are the perfect classroom examples of diversification in a genus. The floral colors can be purple, rose, yellow, yellower, orange, white, and more. The flowers can be solitary, in cylindric drums, in narrow spikes, in globes, in candelabras, and so forth and so on.
They are reminiscent of Orchid flowers, and sometimes of Orchid flower arrangements. The resemblance to Orchids (or the other way around to be less Orchid-o-centric) includes the overall shapes of the blossoms, especially their horizontal lip, this differing from the other petals and sepals, and textured or patterned. We have overheard observers mistake Polygalas for Orchids. We scoff in derision.
Polygala seeds demonstrate an occasional wildflower adaptation—they have a small ant-snack called an aril (or eliaosome, or caruncle) attached. The ants drag the seeds to the ant nest, which from the seed’s standpoint is a tilled, enriched, weeded, and guarded garden. The aril in Polygala cymosa is small, however, perhaps because the species is semi-aquatic and not in prime ant habitat. It may tilt more toward distribution tricks characteristic of such water-neighbors as Sagittaria, Echinodorus, and Alisma. These have tiny seedlike fruits with raised surface patterns. The similar small P. cymosa seed likewise has a waffle surface pattern. It has been speculated that such “treads” might help small wetland fruits and seeds cling to the muddy feet of waterfowl helping the plants jump to new ponds.